Approach control apparatus for railway signaling systems



Jul 28, 1942. Q PLE 2,291,417

APPROACH CONTROL APPARATUS. FOR RAILWAY SIGNALING SYSTEMS Filed Sept. 20, 1941 INVENTOR ('raw/or .Szaplefi. BY

HIS A'II'TORNEY Patented July 28, 1942 APPROACH CONTROL APPARATUS FOR RAILWAY SIGNALING SYSTEMS Crawford E. Staples, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application September 20, 1941, Serial No. 411,708

'7 Claims.

My invention relates to approach control apparatus for use in railway signaling systems of the coded track circuit class and it has special reference to the employment of such apparatus for approach controlling various signaling functions without the use of line wires.

Generally stated, the object of my invention is to provide improved approach control apparatus for use with multiple single direction running track that is equipped with coded track circuit signaling facilities of conventional non-linewire character.

A more specific object is to enable a plurality of parallel tracks to govern the approach energization of wayside or other signaling apparatus through the medium of but a single channel of coded feed back track circuit control.

Another object is to provide a multiple track non-line-wire approach control scheme which is broadly useful, universally applicable and highly practical.

In practicing my invention I attain the above and other objects and advantages by providing coded feed back control channel facilities for the sections of only one of the parallel tracks in the single direction running group; equipping the sections of each of the remaining tracks in the group with means whereby a shunt of the section rails causes the channeled section directly paralleling the shunted one to discontinue its feed back energy transmission; and arranging that such discontinuance will light advance wayside signals for all of the tracks or perform any other function of approach. energization that may be desired.

I shall describe one form of approach control apparatus embodying my invention and shall then point out the novel features thereof in claims.

In the single view of the accompanying drawing this illustrative embodiment is disclosed in conjunction with the parallel sections of two single direction running tracks that are equipped with wayside signaling facilities of the coded track circuit class.

In that drawing view the two tracks just named are designated as track I and as track 2. Both of these tracks carry traflic in the single direction that is designated by the arrows (or from left to right in the diagram) and each is divided by insulated rail joints 3 into a plurality of successive sections of customary block signal control type.

Only one such section of each track has been illustrated. In both instances this section extends from an entrance end location M to an exit end location N and in each instance it is guarded by the usual wayside signal Sm installed as shown at its entrance end. Similar signals for all remaining sections in the protected stretch are typified by devices lSn and 281i at location N.

Control of each of these system signals is effected by coded track circuit facilities of conventional character. Those shown for section MN of track 2 are illustrative. They comprise: (1) a code following track relay 2TB at the section entrance operated by energy received from the section rails and selecting the indication of signal 28111. through the medium of decoding apparatus 2DAm; (2) a track battery TB at the section exit periodically connected with the section rails by a contact 5 of a coding device ZCR; and (3) code transmitter means (not here shown) for continuously operating the device 20R at one or another of the usual plurality of distinctive code rates.

Selection among these rates (which in a typical three indication system may consist of '15 and energy pulses per minute) is made in accordance with advance traific conditions by the decoding apparatus 3DAn functioning in customary manner. That decoding apparatus (details not here shown) is controlled in the usual fashion by an associated track relay TR (also not shown) at location N and it performs the further function of selectively setting up a lighting circuit for one or another of the lamps (G, Y and R in the typical three indication system above referred to) of the associated signal 2811. In the arrangement here shown, current for energizing those signal lamps is derived from power source terminals plus and minus.

An automatic block signaling system of the coded track circuit type just described for track 2s section MN operates without the aid of line wires and in representative form it includes all of the elements above named.

Corresponding coded track circuit elements also are provided for track is section MN. These include an exit end track battery ITB and associated coding device ICR plus an entrance end track relay [TR and associated decoding apparatus lDAm. Signal lSm is controlled through that apparatus while signal iSn is controlled through corresponding apparatus lDAn at location N.

Multi-track stretches of main line road totalling many miles now are equipped with signal control apparatus which duplicates that just described for tracks I and 2. In the interests of power economy and for other obvious reasons it is desirable that the wayside signals S for such multi-track stretches be energized only when an approaching train requires an indication therefrom.

Past practice in rendering this and other signaling functions active only upon the approach of a train has been to provide each of the tracks in the single direction running group with its own individual channel of approach energization control. Numerous forms of such individual channel control which operate both with and without line wires now are known.

Examples of the latter include the coded feed back schemes of: (1) Frank H. Nicholson Patent 2,021,944, dated November 26, 1935; (2) Crawford E. Staples Patent 2,228,792, dated January 14, 1941; (3) Herman G. Blosser Reissue Patent 21,783, dated April 29, 1941; (4) Louis Girardin application Serial No. 315,553, filed January 25, 1940; (5) Frank H. Nicholson application Serial No. 385,400, filed March 27, 1941;

and (6) still additional cases of comparable character.

Utilization of any of these schemes with the multi-track combination of the annexed drawing obviously requires that each and every one of the tracks in the single direction running group have its coded track circuit signal control equipment supplemented by coded feed back approach control facilities. While such an arrangement is, of course, satisfactory from an operating or performance point of View, it requires so much feed back apparatus that commercial adoption cannot, in many instances, be justified.

To reduce these apparatus requirements to a state of simplicity which is competitive with line- Wire schemes of approach control: (1) I provide coded feed back control channel facilities for the sections of only one of the parallel tracks in the single direction running group; (2) I equip the sections of each of the remaining tracks in the group with means whereby a shunt of the section rails causes the channeled section directly paralleling the shunted one to discontinue its feed back energy transmission; and (3) I arrange that such discontinuance will light advance wayside signals for all of the tracks or perform any other function of approach energization that may be desired.

In the illustrative two-track organization of the drawing my improved approach control combination includes: (1) at the exit location N an approach relay AR having a contact 9 which normally disconnects signals lSn and 2Sn from their lighting source, a detector relay KR having a contact l3 which normally maintains relay KR picked up, and circuit elements for connecting relay KR in energy receiving relation with the rails of track is section MN; and (2) at the entrance location M a source KB of feed back energy, an impulse relay IR having contacts l2l3 which connect the rails of track is section M-N with that source during each 01f period of the received signal control code, and a code detecting relay 2H for track 2s section M--N having a contact H which effects the removal of all feed back energy from track is section MN whenever track 2s section M-N becomes shunted.

The represented combination of exit end devices ICRITBKRAR is an exact duplicate of that shown by Fig. 3 of the earlier referred to Nicholson application Serial No. 385,400. Alternatively, however, it might be organized as shown in one of the other coded feed back applications or patents of the earlier named list. Its purpose is to keep relay AR picked up as long as device KR receives off period pulses of feed back energy from the rails of track ls section MN.

The represented combination of entrance end devices ITRIBIR likewise is an exact duplicate of that shown by Fig. 2 of the earlier referred to Nicholson application Serial No. 385,400.

Alternatively, however, it might be organized as shown in one of the other coded feed back applications or patents of the earlier named list.

. Its purpose is to supply the rails of track ls section MN with off period pulses of feed back energy as long as track relay iTR follows code and impulse relay IRs driving circuit remains intact.

In the complete combination of the present invention, provision is made for breaking relay IRs driving circuit Whenever a shunt placed across track 2s section MN causes track relay 2TR to cease pole changing transformer 2DT and thereby release code detecting relay 2H. As shown, this provision takes the form of relay 2Hs earlier named contact H which under the conditions just stated disconnects the relay transformer IT from its exciting coupling with decoding transformer I DT. Optionally, of course, this contact I I might be shifted to the secondary side of relay IRs transformer IT.

Under the represented unoccupied conditions for the parallel sections MN of both tracks I and 2: (1) coded signal control energy from source 2TB operates track relay 2'I'R and holds detecting relay 2H picked up; (2) coded signal control energy from source lTB operates track relay ITR and causes impulse relay IR to shift the connection of track ls section rails from relay TR to feed back source KB during each off period of the received signal code; (3) the resulting off period pulses of feed back energy flow over track Is section rails and cause detector relay KR recurrently to energize relay AR over contact l8; and (4) the thus energized approach relay AR holds contact 9 continuously picked up and thereby keeps wayside signals 1811 and 2812 both disconnected from their energizing sources.

Entry of a train into section MN of track I now produces the following effects. The resulting shunt of the section rails: (l) deenergizes relay lTR and thereby causes device IR to discontinue the feed back energy supply; and (2) removes all feed back energy from the detector relay KR at the section exit and thereby prevents contact [8 from transmitting pick-up current to the approach relay AR. As a result, that relay AR releases and thereby completes (at contact 9) energizing circuits for both of the wayside signals lSn and 2Sn. In consequence, each of those signals now lights the particular lamp that is selected by the associated decoding equipment DAn.

As soon as the rear of the track I train clears location N, track relay ITR once more responds to signal code energy, impulse relay IR causes off period pulses of feed back energy again to be supplied to the section rails, that energy is transmitted to and operates exit and relay KR, and that operation picks up approach relay AR and restores both of the signals lSn and 2Sn to their normally inactive state.

Assume, now, that while track ls section MN is vacant a train comes into section MN of track 2. The resulting rail shunt deenergizes relay 2TR and thereby releases device 2H. That release breaks (at contact I l) the driving circuit of track ls impulse relay IR and thereby removes all feed back energy from the rails of track Is section MN. As a result, track ls detector relay KR becomes inactive, approach relay AR releases and contact 9 again causes lighting current to be supplied to both of the wayside signals lSn and 2Sn.

As soon as the rear of the track 2 train clears location N, track relay ZTR once more responds to signal code energy and picks up relay 2H. That pick-up recompletes (at contact H) the driving circuit for track is impulse relay IR and causes off period pulses of feed back energy again to be supplied to the track I section. As before, that energy operates track ls detector relay KR and by picking up the approach relay AR restores both of the signals to their normally inactive state.

As herein disclosed my just described approach control facilities are applied to only two parallel tracks in a single direction running group. Application to three or more such tracks is, however, readily possible. To make such an extended application it is merely necessary to equip each additional track with a section entrance H relay and to include in the driving circuit for the parallel track ls impulse relay m. a front contact thereof in the serial manner typified by element H of device 2H. Quite obviously, now, a release of the H relay for any of the additional tracks will discontinue track ls feed back supply and thereby release the section exit approach relay AR.

While, moreover, I have explained my invention in an application wherein the lights of multitrack wayside signals only are approach controlled, it will be understood that other comparable functions may be provided for instead of or in addition to the illustrative one just named. One such further function might consist in supplying the rails of the multi-track sections to the rear of the approach lighted signals with coded alternating current which is suitable for the control of train carried cab signals (not here shown) another might consist in operating highway crossing signals (also not here shown) or the like; a third in the approach lighting of station platform lights; and a fourth in the locking of track switches at cross-overs in automatic territory.

From the foregoing it will accordingly be seen that I have provided simplified approach control apparatus for use with single direction running multiple track that is equipped with coded track circuit signaling facilities of conventional non-line-wire character. More specifically: (1) I have enabled a plurality of parallel tracks to govern the approach energization of wayside or other signaling apparatus through the medium of but a single channel of coded feed back track circuit control; and (2) I have provided a multiple track non-line-wire approach control scheme which is broadly useful, universally applicable and highly practical.

As my improved approach control facilities are entirely a function of the track circuits and apparatus which is directly associated therewith, they are independent of the coding and decoding apparatus of the coded signaling systems with which they are combined and hence they are usable with signaling systems which employ a wide variety of different types and forms of such apparatus.

Although I have herein shown and described only one form of approach control apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

1. In combination, a first railway track which includes a first track section, a second railway track which parallels said first track and which includes a second track section having entrance and exit ends at substantially the same locations along the right of way as are those of said first section, means at the second section exit for supplying coded signal control energy to the second section rails, means at the first section exit for supplying coded signal control energy to the first section rails, means at the first section entrance for further supplying the first section rails with feed back energy which under vacant section conditions is transmitted to said first section exit, means at the second section entrance for detecting reception thereat of said second section coded energy and for cutting off the supply of said first section feed back energy whenever said reception of the second section coded energy becomes discontinued, first and second traffic controlling devices at the exit ends of said first and second track sections, and means governed by the said feed back energy which is received at the said first section exit for maintaining both of said trafiic controlling devices deenergized as long as said feed back reception continues and for completing an energizing circuit for each of those devices whenever said feed back reception becomes discontinued due to a train shunt being placed across the rails of either of said first and second track sections.

2. In combination, a first railway track which includes a first track section, a second railway track which parallels said first track and which includes a second track section having entrance and exit ends at substantially the same locations along the right of way as are those of said first section, means at the second section exit for supplying coded signal control energy to the second section rails, means at the first section exit for supplying coded signal control energy to the first section rails, means at the first section entrance for further supplying the first section rails with feed back energy which under vacant section conditions is transmitted to said first section exit, means at the second section entrance for detecting reception thereat of said second section coded energy and for cutting off the supply of said first section feed back energy whenever said reception of the second section coded energy becomes discontinued, trafiic governing apparatus at the exit ends of said first and second track sections, an approach relay which completes an energizing circuit for said apparatus when released and which interrupts said circuit when picked up, and means governed by the said feed back energy which is received at the first section exit for maintaining said approach relay picked up as long as said feed back reception continues and for allowing said relay to release whenever said feed back reception becomes discontinued by the presence of a train in one or the other of said first and second track sections.

3. In combination, a first railway track which includes a first track section, a second railway track which parallels said first track and which includes a second track section having entrance and exit ends at substantially the same locations along the right of way as are those of said first section, means at the second section exit for supplying coded signal control energy to the second section rails, means at the first section exit for supplying the first section rails with signal code energy in the form of recurring on period pulses that are separated by ofi period intervals, means located at the first section entrance and operated by the there received pulses of said signal code energy for further supplying the first section rails with feed back energy in the form of pulses that recur in step with the received code ofi periods, means at the second section entrance for detecting reception thereat of said second section coded energy and for cutting off the supply of said first section feed back energy whenever said second section energy reception becomes discontinued, trafiic controlling apparatus at the exit ends of said first and second track sections, and means governed by the said feed back energy which is received at the first section exit for maintaining said apparatus deenergized as long as said feed back reception continues and for completing an energizing circuit for that apparatus Whenever said feed back reception becomes discontinued by the presence of a train in either of said first and second track sections.

4. In combination, a first railway track which includes a first track section, a second railway track which parallels said first track and which includes a second track section having entrance and exit ends at substantially the same locations along the right of way as are those of said first section, means at the second section exit for supplying coded signal control energy to the second section rails, means at the first section exit for supplying coded signal control energy to the first section rails, means at the first section entrance for further supplying the first section rails with feed back energy which under vacant section conditions is transmitted to said first section exit, means at the second section entrance for detecting reception thereat of said second section coded energy and for cutting off the supply of said first section feed back energy whenever said reception of the second section coded energy becomes discontinued, trafiic governing apparatus including a slow release approach relay located at the exit of said two track sections, and means controlled by the said feed back energy which is there received from the first section rails for maintaining said approach relay picked up as long as both of said track sections remain vacant and for releasing said relay whenever either of said sections becomes occupied,

5. In combination, a first railway track which includes a first track section, one or more additional railway tracks which parallel said first track and each of which includes a track section having entrance and exit ends at substantially the same locations along the right of way as are those of said first section, means at the exit end of each of said additional track sections for impressing coded signal control energy upon the rails of the additional section, means at the exit end of said first track section for supplying coded signal control energy to the first section rails, means at the first section entrance for further supplying the first section rails with feed back energy which under vacant section conditions is transmitted to the first section exit, means for cutting ofi" the supply of said first section feed back energy whenever any one of said addition al sections fails to transmit coded energy to its entrance end, a first traffic controlling device at the exit end of said first section, an additional traffic controlling device at the exit end of each of said additional sections, and means governed by the said feed back energy which is received at the said first section exit end for maintaining. all of said traffic controlling devices deenergized as long as said feed back reception continues and for completing an energizing circuit for each and every one of those devices whenever said feed back reception becomes discontinued by the presence of a train in any one of said first and additional track sections.

6. In combination, a first railway track which includes a first track section, one or more additional railway tracks which parallel said first track and each of which includes a track section having entrance andexit ends at substantially the same locations along the right of way as are those of said first section, means at the exit end of each of said additional track sections for impressing coded signal control energy upon the rails of the additional section, means at the exit end of said first track section for supplying the first section rails with signal code energy in the form of recurring on period pulses that are separated by foff period intervals, means located at the first section entrance and operated by the there received pulses of said signal code energy for further supplying the first section rails with feed back energy in the form of pulses that recur in step with the received code oil periods, means for cutting ofi the supply of said first section feed back energy whenever any one of said additional sections fails to transmit coded energy to its entrance end, trafiic governing apparatus including a slow release approach relay located at the exit of said track sections, and means controlled by the said feed back energy which is there received from the first section rails for maintaining said approach relay picked up as long as-all of said track sections remain vacant and for releasing said relay whenever any one of said sections becomes occupied.

'7. In combination, a railroad right of way that includes a plurality of parallel tracks all of which carry traffic in the same direction, traffic governing signals for each of said tracks installed at spaced locations along said right of way and positionally coinciding with the corresponding signals for the remaining tracks, insulated rail joints at each of said signal locations which divide said several tracks into sections that parallel one another and that adjoin at the signal locations, coded track circuit facilities for the said sections of each of said tracks which control the said signals for that track in accordance with advance trafiic conditions and without the aid of line wires, an approach relay at each of said signal locations which maintains all of the track signals thereat deenergized and which permits energizing current to be supplied to these signals only when a train approaches the relay location. feed back track circuit facilities for the sections of one and only one of said tracks for energizing said approach'relays under vacant conditions of all of said tracks whereby then to keep all of said track signals deenergized, and means whereby the presence of a train in any one of said parallel track sections renders the said feed back facilities for the right of way length spanned by that section inactive and by thus releasing the said approach relay at the exit end of that length effects the energization of all of the said track signals at the location of the released relay.

CRAWFORD E. STAPLES. 

